Process for production of low-carbon ferrochrome



HUGH c. SIGARD,- or BUFFALO, NEW YORK, assreiron T0 UNITED STATESrnanonmoys CORPORATION, or NEW YORK, N. Y., A CORPORATION or-nnw YORK.

PROCESS FOR PRODUCTIEON or LOW-CARBON FERROCHROME.

No Drawing.

To all whom it may concern:

Be it known that I, HUGH C. SIoARD, a citizen of the United States ofAmerica, and a resident of the city of Buffalo, county of Erie, andState of New York, have invented a new and useful Process for theProduction of Low-Carbon Ferrochrome, of which the following is a full,clear, and exact description.

This invention relates generally -to a method of manufacturing andproducing low carbon ferro-chrome.

' In another co-pending patent application, identified as Serial No.318,381, filed August 18, 1919, I have described a method of making analloy of iron, chromium and titanium, having a variable carbon content,

the carbon ofwhich is present as a carbid or carbids of iron, chromiumand titanium.

It has been a common practice of the art in decarbonizing 'ferro-chrometo use chrome ore, such as chromite, in combination with burnt lime, ofwhich the latter forms a protective blanket of slag over the moltenmetal. The chrome ore then reacts with the ferro-chrome which containscarbon, and thus in time becomes decarbonized. When such methods areused, the iron oxid which is present in the chrome ore is more readilyreduced than the oxid of chromium, and the consequence is that when thefinal decarbonized ferro-chrome is obtained, it is found to have alowercontent of chromium than the original high carbon material.

In producing this invention I have over- I come the difliculties abovereferred to.

In carrying out my invention I use titanic oxid (TiO for the purpose ofdecarbonization. 'This oxid reacts with the carbon in the high carbonferro-chrome and forms titanium according to the following equation:

It is important to use as a source of the titanic oxid some ore whichcontains the least possible amount of iron oxid, such as rutile.

The reaction is carried out in an electric furnace of the well-knownHeroult type, for example. In this furnace is charged a mixture of thealloy of ferro-chromium, which Specification of Letters Patent. PatentedJ 1 1923,

Application filed September 26, 1919. Serial No. 326,646.

is high in carbon and a quantity of rutilewhich will be sufficient todecarbonize the alloy used. In place of the ferro-chromium I -m'ay usean alloy of iron chromium and titanium, which is high in carbon. Intothis charge burnt lime is placed and the charge is melted down. Theburnt lime forms a protective slag and when the reaction is complete theresulting alloy is tapped from the furnace.

Having thus described my invention, what I claim is: I

1. The method of making low carbon alloys of iron, chromium and.titanium which consists in the decarbonization of a alloys of iron,chromium and titanium,

which consists in charging into an electric furnace a mixture offe-rro-chrom-ium high in carbon, and a sufficient quantity of titanicoxid to decarbonize the alloy.

5. The method of making low carbon alloys of iron, chromium andtitanium, which consists in charging into an electric furnace a mixtureof ferro-chromium high in carbon and a suflicient quantity of rutile todecarbonize the alloy.

6. The method of making low carbon alloys of iron,-chromium andtitanium, which consists in charging into an electric furnace a mixtureof ferro-chromium high in carbon, a suflicient quantity of titanic oxidto decarbonize the alloy, and a suflicient quantity of burnt lime toform a protective slag.

In testimony whereof I have hereunto signed my name.

HUGH c. SIGARD.

